located at the base of the brain near the hypothalamus, secretes the most important hormones for human growth

hypothalamus

the part of the brain that initiates and regulates pituitary secretions

growth hormone (GH)

the only pituitary secretion produced continuously throughout life; affects development of all tissues except the central nervous system and the genitals

thyroine

hormone necessary for brain development and for GH to have its full impact on body size; secreted by the thyroid gland

estrogens and androgens

sex hormones (men and women both have each)

secular trends in physical growth

changes in body size and rate of growth from one generation to the next

general growth curve

rapid growth during infancy, slower gains in early and middle childhood, and rapid growth again during adolescence

neurons

nerve cells that store and transmit information

synapses

tiny gaps between neurons

neurotransmitters

chemicals released by neurons to send messages to one another; cross synapses

programmed cell-death

death of many surrounding neurons as neural fibers and their synapses increase rapidly, which makes room for these connective structures

synaptic pruning

neurons that are seldom stimulated lose their synapses

myelination

the coating of neural fibers with an insulating fatty sheath (called myelin)that improves the efficiency of message transfer

lateralization

specialization of the two brain hemispheres

cerebellum

a structure that aids in balance and control of body movement (at the rear and base of the brain)

reticular formation

a structure in the brain stem that maintains alertness and consciousness

corpus callosum

a large bundle of fibers that connects the two cortical hemispheres

catch-up growth

a return to a genetically influenced growth path once conditions improve

marasmus

a wasted condition of the body caused b a diet low in all essential nutrients; usually appears in the first year of lie when a baby's mother is too malnourished to produce enough breast milk and bottle-feeding is also inadequate

kwashiorkor

caused by an unbalanced diet very low in protein. The disease usually strikes after weaning, between 1 and 3 years of age

obesity

a body weight greater than 20% over the average for the child's age, sex, and physical build

nonorganic failure to thrive

a growth disorder that results from lack of parental love, is usually present by 18 months of age. Infants who have it show all the signs of marasmus- their bodies look wasted, and they are withdrawn and apathetic. But no organic (biological) cause for the baby's failure to grow can be found

pyscho-social dwarfism

a growth disorder that usually appears between 2 and 15 years of age; extreme emotional deprivation can interfere with the production of GH

puberty

young people attain an adult-sized body and become capable of producing offspring

primary sexual characteristics

physical features that involve the reproductive organs

secondary sexual characteristics

features visible on the outside of the body that serve as signs of sexual maturity but do not involve the reproductve organs (for example, breast development and appearance of pubic and underarm hair)

menarche

the scientific name for first menstruation

spermarche

scientific name for first ejaculation

body image

conception of and attitude toward your physical appearance

anorexia nervosa

a tragic eating disturbance in which young people starve themselves because of a compulsive fear of getting fat

bulimia nervosa

young people engage in strict dieting and excessive exercise accompanied by binge eatin, often followed by deliberate vomiting and purging with laxatives